From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by ozlabs.org (Postfix) with ESMTP id 94C202C0090 for ; Thu, 26 Sep 2013 02:45:45 +1000 (EST) Message-ID: <1380127533.3030.319.camel@ul30vt.home> Subject: Re: [PATCH 2/7] iommu: add api to get iommu_domain of a device From: Alex Williamson To: Bharat Bhushan Date: Wed, 25 Sep 2013 10:45:33 -0600 In-Reply-To: <1379575763-2091-3-git-send-email-Bharat.Bhushan@freescale.com> References: <1379575763-2091-1-git-send-email-Bharat.Bhushan@freescale.com> <1379575763-2091-3-git-send-email-Bharat.Bhushan@freescale.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: agraf@suse.de, linux-pci@vger.kernel.org, joro@8bytes.org, linux-kernel@vger.kernel.org, Bharat Bhushan , iommu@lists.linux-foundation.org, scottwood@freescale.com, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2013-09-19 at 12:59 +0530, Bharat Bhushan wrote: > This api return the iommu domain to which the device is attached. > The iommu_domain is required for making API calls related to iommu. > Follow up patches which use this API to know iommu maping. > > Signed-off-by: Bharat Bhushan > --- > drivers/iommu/iommu.c | 10 ++++++++++ > include/linux/iommu.h | 7 +++++++ > 2 files changed, 17 insertions(+), 0 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index fbe9ca7..6ac5f50 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -696,6 +696,16 @@ void iommu_detach_device(struct iommu_domain *domain, struct device *dev) > } > EXPORT_SYMBOL_GPL(iommu_detach_device); > > +struct iommu_domain *iommu_get_dev_domain(struct device *dev) > +{ > + struct iommu_ops *ops = dev->bus->iommu_ops; > + > + if (unlikely(ops == NULL || ops->get_dev_iommu_domain == NULL)) > + return NULL; > + > + return ops->get_dev_iommu_domain(dev); > +} > +EXPORT_SYMBOL_GPL(iommu_get_dev_domain); What prevents this from racing iommu_domain_free()? There's no references acquired, so there's no reason for the caller to assume the pointer is valid. > /* > * IOMMU groups are really the natrual working unit of the IOMMU, but > * the IOMMU API works on domains and devices. Bridge that gap by > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 7ea319e..fa046bd 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -127,6 +127,7 @@ struct iommu_ops { > int (*domain_set_windows)(struct iommu_domain *domain, u32 w_count); > /* Get the numer of window per domain */ > u32 (*domain_get_windows)(struct iommu_domain *domain); > + struct iommu_domain *(*get_dev_iommu_domain)(struct device *dev); > > unsigned long pgsize_bitmap; > }; > @@ -190,6 +191,7 @@ extern int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr, > phys_addr_t offset, u64 size, > int prot); > extern void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr); > +extern struct iommu_domain *iommu_get_dev_domain(struct device *dev); > /** > * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework > * @domain: the iommu domain where the fault has happened > @@ -284,6 +286,11 @@ static inline void iommu_domain_window_disable(struct iommu_domain *domain, > { > } > > +static inline struct iommu_domain *iommu_get_dev_domain(struct device *dev) > +{ > + return NULL; > +} > + > static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova) > { > return 0;